Strange, gentle creatures which lived in peace and harmony with their neighbours millions of years ago may have rivalled or even surpassed Man if they had they not been wiped out by our ancestors, experts have claimed.

They say the bizarrely-shaped creatures, Ediacarans, were neither plants nor animals but a totally unique order of life.

Experts believe the creatures appeared out of mould and algae that characterised the beginnings of life on Earth about 600 million years ago and evolved rapidly to become the Earth's most sophisticated inhabitants.

Mark McMenamin, Professor of Geology at Mount Holyoke College in Massachusetts in the US, believes the Ediacarans were literally eaten out of existence by the influx of new animal predators.

He goes further by controversially claiming that by the time they were killed
off, the Ediacarans were already showing signs of awareness and intelligence.

The Ediacarans, named after the Ediacara Hills in South Australia where their
fossils were first discovered, developed into a multitude of strange forms,
including fronds and bulbs.

A pre-historic Eden

However they had no teeth, claws or other physical features with which to prey
on their neighbours. Instead they inhabited a pre-historic Eden, photosynthesising their own food, absorbing nutrients from the water around them.

Some were attached to the sea bed, others were free-floating, and a few may have had crude fins.

But Professor McMenamin points out that about the time of their demise, 50 million years ago, the Ediacarans began to sprout intriguing new body parts such as simple antennae.

In Professor McMenamin's view the creatures were beginning to evolve senses and even crude brains.

A life cut short

"Ediacarans were on a trajectory in which they would have developed into intelligent life, but it was cut short," he said in a report published in the New Scientist magazine.

"They were developing ways to pick up environmental cues and process that
information in ways that would allow them to adapt better and leave more
progeny.

"Ediacarans represent the first evidence of anything like intelligence on
Earth."

Other researchers have dismissed his ideas, claiming the Ediacarans were in
fact the forebears of primitive animals such as jelly-fish.

For decades the accepted view was that Ediacarans were animal ancestors.

Then
in 1982, Adolph Seilacher, from the University of Tubingen in Germany, announced
that Ediacarans were not animals at all but a now-extinct class of life by themselves.